The invention relates to a hydraulic braking assembly of a vehicle comprising a hydraulic fluid tank, said tank being equipped with a hydraulic fluid level sensor. The aim of the invention is to simplify the fitting of a hydraulic braking assembly. Another aim of the invention is to reduce the manufacturing cost of this hydraulic assembly.
The invention can be applied to the motor vehicle field but could be applied to other fields.
FIG. 1 diagrammatically illustrates a hydraulic braking assembly 1 of the state of the art. This hydraulic braking assembly 1 is formed by an electric servomotor 2 supporting braking (brake booster), a hydraulic master cylinder 3, a hydraulic fluid tank 4 and at least one hydraulic braking circuit (not represented). The servomotor 2 comprises an electric motor 5, a computer 6 and a battery 7. The computer 6 forms an electronic control device and is connected to the battery 7. A brake pedal (not represented) is connected to a control rod 8, which is in turn mechanically connected to the servomotor 2. The computer 6 is also connected to a central control member (not represented) by a first cable 9. The central control member collects all the electronic vehicle data. The central control member may include a dashboard to which the first cable 9 is connected by means of a CAN (Controller Area Network) type bus.
The tank 4 is mounted on the master cylinder 3 to feed at least one chamber (not represented) of the master cylinder 3 with fluid. The hydraulic braking circuit connects the chamber of the master cylinder 3 to a braking device (not represented) mounted on a wheel of a vehicle.
The electric servomotor 2 comprises a screw/nut assembly 10 converting a rotational movement of the rotor-forming nut of the electric motor 5 into a rotational movement of the screw which displaces a support piston 11 toward the master cylinder 3. The servomotor 2 is actuated by the control rod 8 displaced by the brake pedal. A force sensor (not represented) measures the force applied to the control rod 8 by the driver via the brake pedal. The information concerning the force applied to the control rod 8 is transmitted to the computer 6. This computer 6 then generates, on the basis of this information, a control command to the electric motor 5 so as to displace the support piston 11 according to the force exerted on the control rod 8.
The fluid tank 4 contains an amount of hydraulic fluid that makes it possible to permanently feed the chamber of the master cylinder 3.
A hydraulic fluid level sensor 12 is placed inside this tank 4. This sensor 12 is, in one example, of the REED glass envelope type or of the HALL effect type (or proximity magnetic sensor). In the case of a REED glass envelope sensor, it is formed by two electromagnetic blades and by an electromagnet. The two blades are in contact with one another as long as the electromagnet is placed above the blades, that is to say that the fluid level is above the blades. When the electromagnetic approaches the blades, they end up separating because of the proximity of the electromagnet tending to separate the blades from one another. The electrical contact is then broken and this information is transmitted to the driver via a light and/or audible signal communicated by a dashboard.
The sensor 12 is electrically connected to the central control member by a second cable 13. The central control member may also include a central computer to which the second cable 13 is linked.
A first cable 9 and a second cable 13 are therefore necessary to connect the hydraulic braking assembly 1 to the central control member. The problem is that the second cable 13 is bulky, possibly measuring up to 50 cm to reach the central control member. This second cable 13 may be inadvertently caught when the bonnet of the vehicle has to be opened to check the condition of at least one member of the vehicle or to repair at least one member. This second cable 13 may then be cut or at least hinder the operator. To avoid the possible hindrance of this second cable 13, it can be arranged in a controlled manner inside the space enclosed by the bonnet of the vehicle. To do this, this second cable 13 may be pressed against a wall of the cowl while being clipped, or else glued or clipped against another wall of a member of the vehicle. However, the surface of certain areas of the cowl (those exposed to external climatic variations), or the surface of a given member, may be subject to temperature variations that may damage the quality of this second cable 13. Notably, the heat or cold may impede correct operation and/or cause premature wear of this second cable 13. It is therefore important to be careful to choose the correct places, that is to say those which present least risk of damaging the quality of this second cable 13.
Fitting such a second cable is therefore difficult, tedious and costly.